Chevy Small Block Part 11 - Pt. 11: Tuner's Delight

In our last segment, Danger Mouse (DM) practically blew the roof off when it made more than 600hp on pump gas with help from a "little" Weiand blower. That was super-cool and for a short while we couldn't figure out what to do next that could top that. But after our visit to the COMP Cams/Superflow Advanced Engine Technology Conference in Colorado Springs, Colorado (see: "Power of the Spoken Word," page 90), and hearing Lance Ward from Fuel Air Spark Technology (F.A.S.T.) talk about the power and benefits of EFI, we knew what we had to do next.

EFI PotentialAlthough it's still relatively expensive, the benefits of EFI far out-weigh its costs. EFI is easier to start and runs better on the street. Its self-tuning capabilities make it adaptable to any situation. Cold mornings, hot summer days, mountain driving, or all-out hauling, EFI can handle them all and will probably save you a few bucks at the pump in the long run too. Today's EFI systems are very easy to install and if you turn a computer on and plug it in, then you can tune EFI.

3/14

As the aftermarket sees the value in EFI and continues to hire and train more computer-savvy tech heads, the average guy on the street will benefit from the true plug-and-play systems being developed. Most of the aftermarket EFI systems from companies like Accel, F.A.S.T., Holley, and others come with ready-made fuel and spark timing tables, also known as "maps", to get any car going once the system is installed. And if you're laptop is plugged in, you can have a buddy tune the car as you drive without ever lifting the hood!

And trust us when we tell you that you do not have to be a computer wiz to tune these things. All it takes is a fair understanding of how an engine burns fuel to make power and you're already about 75% there. Then it's just a matter of learning the operating system's ins and outs, some computer knowledge is helpful here, and you'll be tuning for power. If we can do it, anyone can.

4/14

Dyno Testing Part 11 Carbureted PowerSince we're always trying to compare our tests to something relevant, we wanted to compare EFI power to a properly tuned carburetor. As it turned out, the carb made almost as much power as the EFI. And it took us a whole day's worth of tuning to get the EFI past the Demon carb at peak power. But look at the extra low-end torque the EFI made in Test 22 (w/ 30-lb/hr injectors at 50 psi) and you'll see one obvious benefit of EFI.

EFI MagicTuning an EFI motor is a lot more fun than tuning a carbureted one. The reason is simple; you don't have to lift the hood. Once the system is running, you just need to check the ignition advance with a timing light to make sure it matches the spark setting in the ECU and then close the hood and start driving. In our case, we shut the dyno cell door and started pulling.

The F.A.S.T ECU can work with any electronic distributor, but you get the most accurate trigger signal and fuel/spark control from a crank-trigger like this MSD PN 8600.

It's necessary to properly "phase" the rotor when running a crank trigger. Dyno-Steve shines a timing light though a hole in a modified distributor cap with the engine running to check the rotor phasing. The big power DM made this month is also thanks to a special big guy. Harv St. Mary from Harv's Performance came out on his own time to help us tune it to peak perfection. We owe him big thanks.

One of the other really trick features of aftermarket EFI is the ability to "data-log" your performance. This means the computer records the info from a run and plays it back on the laptop so you can diagnose a problem or compare figures from previous runs for fine-tuning.

Although the math told us that 30-lb/hr injectors were right on, we wanted to try bigger injectors for more power. And just like installing a too-big carb, the large injectors made a little more peak power, but hurt the bottom end.

Learn more about Fuel Air Spark Technology and the secrets of EFI tuning in this month's How It Works. Read more only at www.chevyhiperformance.com, the official website for Chevy High Performance Magazine! » Read More

Get the latest info on LSX performance with exclusive coverage of the 2008 Advance Engine Technology Conference. Only at www.gmhightechperformance.com, the official site for GM High-Tech Performance Magazine. » Read More